Numerous types of jacketed electrical cables are exposed to an environment which can corrode their inner metallic conductors. One such cable is drop wire, which is an electrical cable used to bring a cable TV signal from a common line into an individual home. Typically, drop wire is either buried underground, or run in the open where it is exposed to the environment. In either case moisture can penetrate the cable through nicks and cuts in its protective outer jacket, corrode the metallic conductors, and require replacement of the cable. To a cable company which must maintain thousands of miles of drop wire in the field, an improvement in the moisture resistance of the drop wire will result in a significant saving in cost.
To prevent corrosion within cable, the interiors of cables have been flooded with semisolid hydrophobic materials, such as waxes, greases, etc. Exemplary of this approach are U.S. Pat. Nos. 3,875,323 to Bopp and 4,110,137 to Beach. A disadvantage of this design is that the flooding material can flow out of the cable through cuts in its jacket, resulting in a decrease in corrosion resistance. This is particularly true at the cut ends of the cable (making such cable messy to handle), and where the cable is exposed to wide temperature fluctuations.